code: def _set_state_impl(self, key, param):
      pass
  
file_path: nnabla/python/test/solver/test_sgd.py
imports: import pytest
  import nnabla.solvers
  import numpy
  from solver_test_utils import solver_tester, RefSolver
  from nbla_test_utils import list_context
label_desc: Use image node_id 2 for calling the RefSgd obj's underlying member method code with example usage: obj._set_state_impl(key, param) without return types